Indttstrie aktiengesellschaet



Pat ent ed Oct. 4, 1932 INDUSTRIE AKTIENGESELLSCHAFT, 0F FRANIHORT-ON THE-MAIN, GERMANY fi-IHYDROXY-D'ERIYATIVES 0F ALKYL-PYRIDINES AND PROCESS OF PREPARING THEM No Drawing. Application filed November 6', 1929, Serial No. 405,289, and. in Germany November 26, 1928. V

The present invention relates to ,B-hydroxyderivatives of alkyl-pyridines and to a process of preparing them.

I have found that the ,B-hydroxy-derivativesof alkyl-pyridines can be prepared from the corresponding sulphonic acids by fusing them together with caustic alkalies.

For this purpose thealkali salts of alkylpyridine-B-sulphonic acids are heated for 10- 30 minutes with an excess of causticalkalies, preferably .with potassium hydroxide to a temperature of between 180 C. and 250 C., preferably to about 235 C. After cooling the whole is dissolved in a small quantity of water and after neutralization of the solution thus vobtained, the ,B-hydroxy-derivatives is isolated by filtering by suction and .extracting with solvents. I V V The resultant ,G-hydroxy-derivatives of alkyl-pyridines are colorless substances which are soluble in water and alcohol.

The following examples serve to illustrate the invention, but they are not intended to limit it thereto.

1. 7 6 grams of potassium hydroxide and 2 cc. of water are melted in an iron-boiler and at a temperature of about 160 C. 36 grams of the finely pulverized crude potassium salt of a-picoline-sulphonic acid or of the sodium salt of oc-PlCOllIlB-SlllPhOIllC acid (prepared as described in my co-pending U. S. applicatlon Ser. No. 405,288 of even date for: Process for sulphonating pyridine and its homoloques) are slowly introduced while stirring. Then the temperature is slowly raised while stirring. At a temperature of 210 C. reaction occurs and the mass is spontaneously heated to about 235 G.24=O G. Then the mass is further heated for 1520 minutes at this temperature.

After cooling the wholeis taken up in as.

small a quantity of water as possible (about 100 cc.) and neutralized while cooling by means of 78 cc. of concentrated hydrochloric acid, so that there is no longer any alkaline reaction to phenolphthalein. The'mass is. allowed to stand during the night and thenthe separated crystals are filtered by suction,

while washing only very. cautiously with a:

small quantity of water or not at all, because Qne'part 0f the lIYdI'OXY-a-PlCOllIIG is contamed in the separated crystals besides inorganic substances, a second part in the aqueous solution. The l1YdTOXY-oc-Pl00ll118 is preferably obtained from the crystals andthe solution by extracting with solvents. After evaporation of the solvent nearly colorless crystals are obtained which are purified by boiling with dry benzene, in which they are sparingly soluble also at boiling temperature,'then filtered cold by suction and washed with dry fbenzenea By concentrating the mother lye a further small quantity of the crystallized substance is obtained and on evaporating to dryness a tough .oily feebly yellowish substance is obtained which does not crystallize, but otherwise has the same properties as the crystals; it is probably a mixture of hydroxy-bases due to the other bases present in the technical a-picoline. The total yield (10 grams of crystallized hYdlOXY-cz-PlCOllHG and 3 grams of tough oily hydroxy-bases) amounts to about 75%, calculated upon the crude sulfonate.

ThG B-llYdIOXy-wPlCOllIIG melts at 164- C5166" 0.; it sinters a little at 155 C;

The,8 l1ydroxy-u-picoline is readily soluble in water, in a-picoline'and in alcohol, from which it can be obtained in the form of very beautiful crystals. It is sparingly soluble even in boilng benzene, moderately soluble in ether, better soluble in acetic ester. When mixed with FeCl the aqueous solution gives a reddish-brown coloration. It boilswithout decomposing and again solidifies on cooling to crystals. The smell is only feeble. In a solution rendered alkaline by sodium carbonate it couples well with diazotized paranitraniline with a bluish-red coloration, when treated with an acid, it turns to yellow. I

2. 90 grams of potassium hydroxide and 5 cc. of water are melted in an iron-receptacle at 140 (1, 80 gramsofthe potassium salt of picoline-B-sulfonic acidare introduced and the whole is heated while stirring. With evolution of much heatthe temperature rises to 210 0:235 G, which is kept for about 4- 5 hour. Thecooled melt is dissolved in 100,

,rFiclE 7 OTTO WULFF, OF HOFHEIM-IN-TAUNUS, GERMANY, .ASSIGNOR TO I. Gr. FABBEN- 120 C. and boils at 285 C.-290 C. while slightly decomposing.

It is easily soluble in alcohol, moderately soluble in water, scarcely soluble in cold benzene, and well soluble in warm benzene.

The solution rendered alkaline by sodium carbonate couples with 'diazotized paranitraniline with development of a red color,

V on addition of acid this color turns to yellow.

- Ser.

' by filtering, by suction and extracting with 3. In the same manner as indicated in Example 1, the potassium saltof a-methyl-B'- ethyl-pyridine-,8-sulfonic acid (prepared as described in my co-pending U. S. application No. 405,288 of even date for: Process for sulphonating pyridine and its. homologues) is molten. The ,8-hydroxy-,8- ethyl-a-picoline is obtained with a good yield. It melts at 170 C.173 C. The solubility and the color produced by coupling are similar to those of the B-hydroxy-a-picoline. In thesame manner the ,fi-sulfonic acids of other alkyl-pyrid'ines, that is to say of such pyridines as have more alkyl-groups or higher alkyl groups, are transformed into their hydroxy-derivatives.

In the preceding examples there can be used instead of potassium hydroxide also sodium hydroxide or another caustic alkali.

I claim:

1. The process of preparing ,B-hydroxyderivatives of alkyl-pyridines, which consists in heating for 10-30' minutes to about 180 C.250 C. the alkali metal salts of the corresponding sulfonic acids with an excess of caustic alkalies while slowly beginning the heating, taking up the'product after cooling in a small quantity ofwater, neutralizing and isolating the resultant B-hydroxy-derivative solvents.

2. The process of preparing ,8-hydroxycorresponding sulfonic acids with an excess of potassium hydroxide while slowly beginning the heating, taking up the product after cooling in asmall quantity of water, neutralizing andisolating the resultant B-hydroxyderivative by filtering, by suction and extracting with solvents.

The process of preparing ,B-hydrOxyderivatives' of alkyl-pyridines, which consists in heating for .10-30 minutes to about 235 C. the alkali metal salts of'the corre-- sponding sulfonic acids with an excess'of potassium hydroxide while slowly beginning the heating, taking up the product after cool.

ing in a small quantity of water, neutralizing and isolating the resultant fi-hydroxyderivative by filtering, by suction and extracting with solvents. g

4:- The process of preparing substances of the following formula:

wherein the one Xstands for methyl, the other X for hydrogen, which consists in heating for 10-30 minutes to about 180- G.250 G. the alkali metal salts of the corresponding sulfonic acids with an excess of potassium hydroxide while slow- 1y beginning the heating, taking up the product after cooling in a small quantity of water neutralizing and isolating the resultant B-hydroxy-derivative' by filtering, by suction and extracting'with solvents.

5. The process of preparing substances of the following formula:

wherein theone X stands for methyl, the other X for hydrogen, which consists in heating for 1030 minutes to'about 235 C. the alkali metal salts of the corresponding sulfonic acids with an excess of potassium hydroxide whileslowly beginning the heating, taking up the product after cooling in a small quantity of water, neutralizing and isolating the resultant ,B-hydroxy-derivative by filtering, solvents." V

6. The process of preparing ,BhydIOXy-ocpicoline, which consists in heating for 10-30 minutesto about 180 G.-250 C. the potas-. sium salt of. oc-PlCOllIlQ-B-SlllfODiC ac-id'with an excess of potassium hydroxide while 810W.- lybeginning the heating, taking up the product after cooling in a small quantity of water, neutralizing and isolating the resultant ,8- hydroxy-derivative by filtering, by suction and extracting with solvents.

7 The process of preparing ,8-hydroxy-apicoline, which consists in heating for 10-30 minutes to about235 O. the potassium salt of oc-PlCOllIlQ-B-SlllfOIllC acid with an excess of potassium hydroxidewhile slowly begin ning the heating, taking up the product after the B-hydroxy-deriva I by suction and extracting with g 9. As new products, the compounds of the following formula:

XV N wherein the one X stands for methyl, the other X for hydrogen.

10. As a new product, the B-hydroXy-amethylpyridine, forming colorless crystals which are easily soluble in water and alcohol, (lifficultly soluble in benzene. 11. As a new product, the ,B-hyclroxy-B- ethyl-a-methylpyridine, said product being easily soluble in water and alcohol, diflicultly soluble in benzene.

In testimony whereof, I affix my signature.

OTTO WULFF. 

